Changes in amino acid concentration in plasma and type I and type II fibres during resistance exercise and recovery in human subjects.
Eight male subjects performed leg press exercise, 4 x 10 repetitions at 80% of their maximum. Venous blood samples were taken before, during exercise and repeatedly during 2 h of recovery. From four subjects, biopsies were taken from the vastus lateralis muscle prior to, immediately after and following one and 2 h of recovery. Samples were freeze-dried, individual muscle fibres were dissected out and identified as type I or type II. Resistance exercise led to pronounced reductions in the glutamate concentration in both type I (32%) and type II fibres (70%). Alanine concentration was elevated 60-75% in both fibre types and 29% in plasma. Glutamine concentration remained unchanged after exercise; although 2 h later the concentrations in both types of fibres were reduced 30-35%. Two hours after exercise, the plasma levels of glutamate and six of the essential amino acids, including the branched-chain amino acids were reduced 5-30%. The data suggest that glutamate acts as an important intermediate in muscle energy metabolism during resistance exercise, especially in type II fibres.
Blomstrand
Eva
E
Swedish School of Sport and Health Sciences, Box 5626, 114 86, Stockholm, Sweden. eva.blomstrand@gih.se
Essén-Gustavsson
Birgitta
B
D000328:Adult; D000596:Amino Acids / Q000097:blood*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism*; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism*; D055815:Young Adult
D000596:Amino Acids